Bearing cage segment including joint edge for welding

ABSTRACT

A sheet metal bearing cage segment includes a first ring section, at least one second ring section and a plurality of bridges connecting the first and second ring sections and forming pockets for receiving at least one rolling element. The first ring section and/or the at least one second ring section includes a circumferentially facing joint edge configured to be connected to another circumferentially facing joint edge to form a to-be-formed pocket. The joint is spaced from the plurality of bridges, and the joint edge is formed by laser cutting. The joint edge may include a chamfer on a radially outer side and/or on a radially inner side.

CROSS-REFERENCE

This application claims priority to German patent application no. 102019 201 560.3 filed on Feb. 7, 2019, the contents of which are fullyincorporated herein by reference.

TECHNOLOGICAL FIELD

The present disclosure is directed to a bearing cage segment of a sheetmetal cage having an improved joint edge for welding and to a sheetmetal cage including such a bearing cage segment.

BACKGROUND

Bearing cages are known from the prior art that are composed of one ormore rounded cage segments, made of sheet metal, that are respectivelyconnected to one another at their joint edges, for example by welding.

Here it is known to produce the structure and contour of such bearingcage segments by punching and stamping. For this purpose in a first stepa metal band is intermittently moved in the longitudinal direction,wherein transversely extending slots are formed by a punch press. In afurther step the metal band is cut to length using a transverse cuttingdevice so that a ladder-shaped sheet metal part is formed, wherein the“rungs” of this part form bridges of the bearing cage segment, the slotsof the part form pockets of the bearing cage segment, and the “siderails” of the part form the ring sections of the bearing cage segment.In a subsequent step the ring sections are then bent to a desired radiusof curvature by round molds.

The cutting-to-length is usually effected here in the region of a pocketso that a joint edge is formed on each of the ring sections and a“partial pocket” is formed therebetween. When assembling the bearingcage segment into a finished cage, these joint edges—after apost-processing, which is to be discussed in more detail below—arewelded together with two further, analogously formed joint edges, sothat a “welding pocket” is formed by the connecting of the “partialpockets.”

Cutting-to-length is a punching process in which a combinedshear-cutting and breaking occurs. For this reason the joint edges ofthe ring sections, which joint edges are formed by the cutting-to-lengthof the sheet metal and are directed in the circumferential direction,are not dimensionally stable enough to be able to serve directly as awelding surface. The post-processing mentioned here is thereforerequired. In addition, a cutting liquid is typically used during thecutting-to-length which must still be removed for a further processing.

The post-processing here is necessarily associated with a materialremoval. If, therefore, after the bearing cage segment has been bentround the post-processed joint edges were to simply be welded to thecorresponding joint edges opposing in the circumferential direction,then at this connecting point a welding pocket would be formed which,viewed in the circumferential direction, would have a smaller width thanthe other pockets. For this reason, according to the prior art, aftercutting to size the ring sections are first shortened by approximately acomplete pocket width and only then post-processed, so that with respectto the desired pocket width they have the correct length for connectingto the opposing joint edges. The final bridge is lost in this way aswaste. Accordingly, in addition to the additional effort of thepost-processing, significant material loss also occurs here.

The quality of the welded joint is of particular significance here sincethe performance of the finished bearing cage significantly dependsthereon.

SUMMARY

It is therefore an aspect of the present disclosure to provide a bearingcage segment that can be manufactured with high reliability at lowerexpense.

In the following a bearing cage segment of a sheet metal cage, inparticular for a needle roller bearing, is provided, which includes afirst ring section, at least one second ring section, and a plurality ofbridges connecting the first ring section and the at least one secondring section to each other, wherein a pocket for receiving at least onerolling element is respectively formed between the bridges. Here thedisclosure is based on the idea that the bearing cage segment includes,on at least one ring section, a joint edge directed in thecircumferential direction, which joint edge is configured to beconnected to another joint edge, wherein the joint edge is disposed inthe region of a pocket to be formed by this connection, and wherein thejoint edge is formed by laser cutting.

Here the bearing cage segment can be configured for single-row ormulti-row bearing cages.

The joint edge can be formed so precisely by the laser cutting that itis directly suitable as a welding edge. In this way a post-processing ofthe welding edge is not required for a reliable welding connection. Inaddition, the bearing cage segment can be individually manufactured bylaser cutting, for example, by a cutting-out from a metal sheet, so thatthe joint edge need not be formed by cutting to length. In this way thematerial loss, as occurs in the above-mentioned prior art, can also beavoided. The manufacturing is thus made easier.

According to one exemplary embodiment, the joint edge includes a chamferon the radially outer side and/or the radially inner side. This designmakes it possible that during the production of the welding connectionno region forms that projects radially or axially over the respectivering section, in particular no projecting weld seam (so-called upperbead).

A particularly simple manufacture of the chamfer is made possible whenit is formed by a reshaping process, i.e., for example, by a rolling ora milling.

According to one exemplary embodiment the entire to-be-formed pocket islaser-cut, wherein the other pockets are preferably punched. Due to thelaser cutting of the to-be-formed pocket, the joint edge can becorrespondingly advantageously configured. However, the producing of the“normal” or “whole” pockets can advantageously be effected by a simpleand rapid punching.

According to one exemplary embodiment, the joint edge is disposedapproximately centrally with respect to the to-be-formed pocket. In thisway—with respect to a plane of the welding connection—a particularlysymmetrical design arises, whereby it can be achieved that undesirablenon-uniform forces that act on the connection during operation of thefinished bearing cage can be avoided, or are at least particularly low.

According to one exemplary embodiment, the ring sections include a jointedge in the region of the to-be-formed pocket. The above-mentionedadvantages thus arise in all ring sections.

According to a further aspect of the disclosure a sheet metal cage isprovided, in particular for a needle roller bearing, that includes atleast one of the above-described bearing cage segments. Here the atleast one bearing cage segment or the plurality of bearing cage segmentsare connected at their joint edges via a material-bonded connection, inparticular welded. The sheet metal cage can thus be manufacturedparticularly advantageously overall. Electrical resistance welding orlaser welding are particularly suitable here as welding. It can thus beachieved that the weld seam is particularly small. The sheet metal cagecan be configured single-row or multi-row.

Further advantages and advantageous embodiments are provided in thedescription, the drawings, and the claims. Here in particular thecombinations of features specified in the description and in thedrawings are purely exemplary, so that the features can also be presentindividually or combined in other ways.

In the following the invention shall be described in more detail usingexemplary embodiments depicted in the drawings. Here the exemplaryembodiments and the combinations shown in the exemplary embodiments arepurely exemplary and are not intended to define the scope of theinvention. This scope is defined solely by the pending claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective representation of a connecting region of abearing cage segment according to an embodiment of the disclosure.

FIG. 2 is a cross-sectional representation of two mutually contactingjoint-edge regions of a bearing cage segment before being welded.

FIG. 3 is the bearing cage region of FIG. 2 after being welded.

DETAILED DESCRIPTION

In the following, identical or functionally equivalent elements aredesignated by the same reference numbers. The direction designationsused in the following—axial, radial, circumferential—always refer to thefinished bearing cage.

FIG. 1 shows an exemplary embodiment of at least one inventive bearingcage segment 1 of a sheet metal cage in the joint region between a firstbearing cage segment end 6 and a second bearing cage segment end 9. Herethe sheet metal cage is can be formed from a single bearing cage segment1, so that the bearing cage-segment ends 6, 9, also referred to here inthe following simply as “ends” 6, 9, are two circumferential ends ofonly one bearing cage segment 1. Alternatively the sheet metal cage caninclude a plurality of bearing cage segments, wherein the first end 6 isone end of a first bearing cage segment 1, and the second end 9 is oneend of a second bearing cage segment 1.

For the sake of simplicity it is assumed in the following that twobearing cage segments 1, 1′ abut against each other by their ends 6, 9.The case that the first end 6 and the second end 9 are formed by thesame bearing cage segment 1 obviously arises in an analogous manner.

Each bearing cage segment 1, 1′ includes a first ring section 2 and asecond ring section 3, and a plurality of bridges 4 connecting the firstring section 2 and the second ring section 3 to each other. In FIG. 1only the final bridge 4 of the first end 6 and the final bridge 4 of thesecond end 9 are shown. Instead of the single-row design of the bearingcage segment 1 depicted here, the bearing cage segment 1 can also beconfigured multi-row, and would then include a first, a second, andfurther ring sections that are each connected to each other by bridges.

A pocket 5 for receiving at least one rolling element is respectivelyformed between the bridges 4. In the example shown the sheet metal cageis a needle-roller-bearing cage, and the pockets 5 are each configuredfor receiving a needle-shaped rolling element.

On its first end 6 on the first ring section 2 the bearing cage segment1 includes a joint edge 7 directed in the circumferential direction,which joint edge 7 is configured to be connected to another joint edge 8of the second bearing cage segment 1′, which joint edge 8 is formed herein an analogous manner on the second end 9 on the first ring section 2.

The joint edges 7, 8 are preferably connected to each other via aconnection, in particular a material-bonded connection, here a weldconnection. Here a laser welding or an electrical resistance welding isparticularly suitable for producing the connection.

As can be seen from the perspective representation of FIG. 1, the jointedge 7 is disposed in the region of a pocket 14 to be formed by theconnection, here also referred to as “welding pocket” 14. Accordingly afirst “partial pocket” is formed by the first end 6, and a correspondingsecond partial pocket by the second end 9, wherein due to the connectionof the joint edges 7, 8 these partial pockets form the to-be-formedpocket 14 or are assembled into the to-be-formed pocket 14.

Here, viewed in the circumferential direction, the joint edges 7, 8 aredisposed approximately centrally with respect to the welding pocket 14.In particular the design can be such that the joint edges 7, 8 lie in aplane that represents a plane of symmetry for the to-be-formed pocket14. However, the joint edges 7, 8 can of course also be disposednon-centrally and/or offset from each other.

The joint edges 7, 8 are formed by laser cutting. The entire partialpocket of the first end 6 of the first bearing cage segment 1, or of thesecond end 9 of the second bearing cage segment 1′, is preferably formedby laser cutting. In this way the joint edges 7, 8 can be shaped soprecisely that a post-processing for suitability as a welding surface isno longer required. Here the surface is directly cleaned by the lasercutting process.

On the second ring section 3 the design in the region of the connectionis preferably analogous to the design on the first ring section 1.

The pockets 5 (without the “welding pocket” 14) can all be formed bypunching.

As can be seen from FIG. 1, guide surfaces 15 of the pockets 5 forguiding the rolling elements can be formed on the bridges 4 and on thering sections 2, 3. These guide surfaces 15 can be formed, for example,by the punching of the pockets 5. The welding pocket 14 can also includecorresponding guide surfaces 15 that can preferably be directly formedhere by the above-mentioned laser cutting of the respective partialpockets.

FIG. 2 shows a cross-sectional representation through the first ringsection 2 in the region of the connection of the joint edges 7, 8,wherein a state is shown wherein the joint edges 7, 8 contact each otherbut are not yet welded.

As can be seen from FIG. 2, the joint edges 7, 8 also include a firstchamfer 10 on the radially outer side, and a second chamfer 11 on theradially inner side. The chamfers 10, 11 serve to receive a radial oraxial material accumulation, for example, an upper bead, as could arisedue to the welding process. In FIG. 3 the state is shown after thewelding. The weld seam 12 formed by the welding can be seen here. Due tothe chamfers 10, 11 no projections are formed.

The chamfers 10, 11 are preferably produced by a reshaping process, forexample, a rolling or milling. The laser cutting and the reshapingpreferably occur with the aid of one and the same machine so that inparticular the bearing cage segment 1 need not be transported to afurther tool to form the chamfers 10, 11.

In summary a bearing cage segment is provided that includes a laser-cutjoint edge that is directly suitable for a weld connection. Here thejoint edge includes a chamfer, whereby the formation of a projection isavoided in the course of the welding.

Representative, non-limiting examples of the present invention weredescribed above in detail with reference to the attached drawings. Thisdetailed description is merely intended to teach a person of skill inthe art further details for practicing preferred aspects of the presentteachings and is not intended to limit the scope of the invention.Furthermore, each of the additional features and teachings disclosedabove may be utilized separately or in conjunction with other featuresand teachings to provide improved bearing cage segments.

Moreover, combinations of features and steps disclosed in the abovedetailed description may not be necessary to practice the invention inthe broadest sense, and are instead taught merely to particularlydescribe representative examples of the invention. Furthermore, variousfeatures of the above-described representative examples, as well as thevarious independent and dependent claims below, may be combined in waysthat are not specifically and explicitly enumerated in order to provideadditional useful embodiments of the present teachings.

All features disclosed in the description and/or the claims are intendedto be disclosed separately and independently from each other for thepurpose of original written disclosure, as well as for the purpose ofrestricting the claimed subject matter, independent of the compositionsof the features in the embodiments and/or the claims. In addition, allvalue ranges or indications of groups of entities are intended todisclose every possible intermediate value or intermediate entity forthe purpose of original written disclosure, as well as for the purposeof restricting the claimed subject matter.

REFERENCE NUMBER LIST

-   1, 1′ Bearing cage segment-   2 First ring section-   3 Second ring section-   4 Bridge-   5 Pockets-   6 First end-   7, 8 Joint edges-   9 Second end-   10 First chamfer-   11 Second chamfer-   12 Weld seam-   14 Welding pocket-   15 Guide surfaces

What is claimed is:
 1. A bearing cage segment comprising: a first sheetmetal ring section, at least one second sheet metal ring section, and aplurality of sheet metal bridges connecting the first ring section tothe at least one second ring section, circumferentially adjacent pairsof the bridges forming pockets for receiving at least one rollingelement, wherein the first ring section and/or the at least one secondring section includes a circumferentially facing joint edge configuredto be connected to another circumferentially facing joint edge to form ato-be-formed pocket, wherein the joint edge is spaced from the pluralityof bridges, and wherein the joint edge is formed by laser cutting. 2.The bearing cage segment according to claim 1, wherein the joint edgeincludes a chamfer on a radially outer side and/or on a radially innerside.
 3. The bearing cage segment according to claim 2, wherein thechamfer comprises a rolled or milled portion of the first and/or secondring section.
 4. The bearing cage segment according to claim 1, whereinthe entire to-be-formed pocket is laser-cut, and the other pockets arepunched.
 5. The bearing cage segment according to claim 1, wherein thejoint edge is disposed midway between the one of the adjacent pairs ofthe plurality of bridges.
 6. The bearing cage segment according to claim1, wherein the first and second ring sections each include the jointedge.
 7. A sheet metal bearing cage including: at least one bearing cagesegment according to claim 1, wherein the at least one bearing cagesegment or the plurality of bearing cage segments are connected at theirjoint edges via a material-bonded connection.
 8. The sheet metal bearingcage according to claim 7, wherein the material-bonded connection is aweld.
 9. The sheet metal bearing cage according to claim 8, wherein theweld is an electric resistance weld or a laser weld.
 10. The bearingcage segment according to claim 1, wherein the joint edge has a radialwidth less than a radial thickness of the bearing cage segment at alocation between one pair of the adjacent pairs of bridges.
 11. Thebearing cage segment according to claim 10, wherein the first ringsection has a radial outer surface and a radial inner surface andincluding a radially inwardly sloped wall connecting the radial outersurface to the joint edge.
 12. The bearing cage segment according toclaim 10, wherein the first ring section has a radial outer surface anda radial inner surface and including a radially outwardly sloped wallconnecting the radial inner surface to the joint edge.
 13. The bearingcage segment according to claim 10, wherein the first ring section has aradial outer surface and a radial inner surface and including a radiallyinwardly sloped wall connecting the radial outer surface to the jointedge and a radially outwardly sloped wall connecting the radially innersurface to the joint edge.
 14. The bearing cage segment according toclaim 10, wherein the bearing cage segment is configured as aneedle-roller bearing cage segment.
 15. A bearing cage segmentcomprising: a first sheet metal ring section, at least one second sheetmetal ring section, and a plurality of sheet metal bridges connectingthe first ring section to the second ring section, adjacent pairs of thebridges forming pockets for receiving at least one rolling element,wherein the first ring section and the second ring section each includea ring section portion having a free end configured to be welded to afree end of another ring section portion of the bearing cage segment orto a ring section portion of another bearing cage segment, wherein thefree ends are formed by laser cutting, and wherein a radial width ofeach of the free ends is less than a radial thickness of the first sheetmetal ring section at a location between one adjacent pair of thebridges.
 16. The bearing cage segment according to claim 15, wherein thefirst ring section has a radial outer surface and a radial inner surfaceand including a radially inwardly sloped wall connecting the radialouter surface to the free end.
 17. The bearing cage segment according toclaim 15, wherein the first ring section has a radial outer surface anda radial inner surface and including a radially outwardly sloped wallconnecting the radial inner surface to the free end.
 18. The bearingcage segment according to claim 15, wherein the first ring section has aradial outer surface and a radial inner surface and including a radiallyinwardly sloped wall connecting the radial outer surface to the free endand a radially outwardly sloped wall connecting the radially innersurface to the free end.
 19. The bearing cage segment according to claim18 configured as a needle-roller bearing cage segment.